Why isn’t my headphone-jack card reader working on Windows Phone?

Some Windows Phones have settings that make connecting to the card reader impossible.
If you are having problems connecting your card reader on Windows Phone,
try disabling both of these settings to connect:

Settings > audio > enhancements > Dolby Headphones

Settings > audio > enhancements > Audio Leveling

Also, some equalizer presets can cause connections problems as well.
If you are experiencing difficulties, check to make sure your equalizer preset is set to ‘None’ by following.